The duration of anestrus in the bitch is highly variable and can last from 4-12 months. It would be important to reduce this time period so as to increase reproductive potential. The present study was designed to develop an effective hormone regimen to induce estrous cyclicity before four months following the last known estrous cycle or whelping. Some of the anestrous bitches used in this study were monitored for changes in ovarian activity by laparoscopy before and after sequential treatments with estradiol, pregnant mare serum gonadotropin (PMSG), and human chorionic gonadotropin (HCG). Serum samples will be analyzed for estradiol, progesterone, and luteinizing hormone.